1. Technical Field
This invention relates to computer peripheral devices and, more particularly, to techniques for preventing vandalism to a computer mouse.
2. Discussion
Computers are finding ever-increasing usage in high schools, universities and other institutions. Most modern-day computers include a computer mouse. The mouse typically includes a housing that is manipulated by the hand to move a trackball located on the housing's underneath surface. Rotation of the trackball is converted into signals which control the location of a cursor or the like on the computer display. The trackball is usually held in place by a removable disk. The disk generally includes some type of gripping surface that allows it to be rotated to remove the ball for cleaning.
FIG. 1 is a generic representation of a computer mouse 10. The removable disk 12 is shown in phantom lines as is the ball 14. Fairly universally, all of the disks 12 include some kind of gripping surfaces to allow the human fingers to grip them so that the disk may be moved to a position in which the disk 12 can be released to allow the ball 14 to fall out so that it can be cleaned.
FIG. 2 shows one class of mouse 10A in which the gripping surfaces are in the form of diametrically opposite indentations 16A and 16B. Other types of computer mice have similar indentations but are in different configurations. These indentations allow the human fingers to grasp the indentations and rotate the disk 12A to a release position. Most disks have undercut tangs 18A, 18B which, in a locked position, engage shelves or fingers formed in the body of the mouse, located on the underneath body surface, to lock the disk in place. When the disk 12A is rotated, in this case clockwise, the tangs 18A, 18B are aligned with reliefs in the mouse body to allow the disk to be removed from the mouse body to permit the ball 14 to be removed. FIG. 2 represents the current configuration of a Microsoft.RTM. mouse. An Apple.RTM. mouse is somewhat similar but it includes swirl indentations on the outer face of the disk. The computer mouse found on many Packard-Bell.RTM. computers includes raised ridges which allow human fingers to move the disk in a linear direction to unlock it to remove the ball.
FIG. 3 shows still another type of computer mouse 10B in which the disk 12B includes two diametrically opposite cutouts 20B, 22B that form gripping surfaces to allow the disk 12B to be similarly rotated to an unlocked position to remove ball 14B. This type of computer mouse generally represents that marketed by Logitek.RTM..
It can be seen, therefore, that almost all currently marketed computer mice employ some type of gripping surface that allows human fingers to freely move the disk and remove the ball. Unfortunately, this freedom of use has been taken advantage by pubescent ner-do-wells or vandals who have no legitimate purpose for removing the trackballs except for deliberate mischievousness. This problem is especially pronounced in secondary educational facilities or other locations that are not specifically monitored. Once the trackball and/or disk has been lost, the computer mouse is obviously unusable. Quite often, it is either difficult or impossible to obtain replacement parts for the vandalized mouse. Accordingly, it often becomes necessary to replace the entire mouse at a sizeable cost to the institution.
Therefore, it would be desirable to provide a computer mouse that is tamper-resistant and which would allow only authorized personnel to remove the trackball for proper maintenance.